Angioplasty is a minimally invasive procedure that involves the insertion of a catheter into the blood vessel for removal of blockages in blood flow. In the conventional approach, the catheter is inserted into the body through the femoral artery and is guided through the lumen of the blood vessel till it reaches a blockage. A stent (superelastic Shape Memory Alloy) is then deployed to open the blood vessel at the blockage and let normal blood flow resume. The surgeon is provided with images that are obtained either by X-ray imaging or by Magnetic Resonance Imaging. These images enable the healthcare provider to track the end point of the catheter (position in absolute coordinates) in real time and determine the future course of insertion.
There are a number of problems associated with the conventional way of performing angioplasty. Specifically, the catheter insertion completely depends on the expertise and dexterity of the surgeon. In the case of intravascular neurosurgery, the catheter is pushed through extremely delicate and complex cranial blood vessels to treat aneurisms in the brain. The repeated insertion of the catheter through several trials could tear the blood vessel at the junction and cause heavy bleeding. This could also result in prolonged operating times and fatigue to clinicians and patients.
The surgeon has no method of estimating the amount of force that is being applied by the tip of the catheter on the walls of the blood vessel. Excessive pressure could rupture the blood vessel with dire consequences. Plaque could also be dislodged which may block blood vessels in the brain or heart and cause a stroke or a myocardial infarction.
The healthcare provider could have prolonged exposure to radiation or be subjected to a high-level of noise caused by the machinery generating magnetic fields for MRI. These pose danger or discomfort to the healthcare providers who perform the procedure over a prolonged period of time.
Another problem with the present procedure of Angioplasty is restenosis. The deployment of a stent at the site of a blockage only provides a temporary solution for resuming blood flow. In 40% of the procedures already done, the plaque begins to build up after a couple of years, a process called restenosis. In addition, the stent, made of superelastic Shape Memory Alloy, has a life of only 10 years. For these reasons, there may arise a need to perform repeated angioplasties for a single patient.
Accordingly it would be advantageous to provide a catheter wherein the movement of the tip can be controlled. Further it would be advantageous to provide a three degree of freedom force sensor that can be attached to a catheter.